Metal Alloy

ABSTRACT

A metal alloy is primarily formed of copper, nickel, magnesium and iron. The main constituents are copper and nickel. The contents of magnesium and iron are increased considerably in comparison with the prior art conventional alloys. The novel alloy has the following constituents in the following proportions (in % by mass and/or % by weight): copper (40% to 61%), nickel (35% to 45%), manganese (3.9% to 10%), iron (0.1% to 5%); and other materials, such as carbon, silicon, aluminum, magnesium, titanium, chromium, rare earths, molybdenum, and/or yttrium (at most 2% in total), with the sum of the components amounting to 100% by mass or, respectively, to 100% by weight.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority, under 35 U.S.C. § 119, of Austrianpatent applications A 733/2007, filed May 10, 2007, and A 2091/2007,filed Dec. 20, 2007; the prior applications are herewith incorporated byreference in their entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a metal alloy which essentiallyconsists of copper, nickel, magnesium and iron. The main constituents ofthe alloy are copper and nickel.

Known alloys of this type have a great number of properties, on thebasis of which they can be used in many technical areas and for variouspurposes. On account of their corrosion resistance, their mechanicalstrength and their ductility, they can be used in particular in thechemical industries, as well as in the oil industry, in chemicalengineering and chemical apparatus construction, and in desalinationtechnology. They can also be used for cable reinforcements, forproducing spectacle frames and in many other technical areas, as well asfor electrotechnical uses. Moreover, these known alloys can be used forcoatings. They can also be used as welding fillers.

These known alloys are produced in the form of castings, powders,plates, sheets, strips, foils, rods, tubes and wires, which serve asstarting products for the production of many components.

In order to satisfy the requirements they have to meet when they areused, these metal alloys must have good processing properties, that isto say they must allow good casting and cold and hot forming, must alsoallow for good welding and good soldering or brazing, must allow goodmachining, good grinding and polishing and also allow themselves to beelectroplated.

All these requirements are met for example by the NiCu30Fe alloymaterial No. 2.4360 in accordance with DIN 17743. That known alloy hasthe following constituents in the proportions given below (in % by massand/or % by weight):

nickel at least 63% copper 28% to 34% iron   1% to 2.5% manganese atmost 2% other materials at most 1%

One of the reasons for the good material properties explained above isthat the individual alloying constituents are completely soluble in oneanother, whereby they form a closed solid-solution series with nomiscibility gaps and as a result of which the alloy is completelyhomogeneous within itself.

The prior art metal alloy and similar further nickel-copper alloys havevery high proportions of nickel, which must be taken into considerationbecause the world market price of nickel is many times higher than theprice of copper, for which reason these known alloys are very expensive.Likewise known copper-nickel alloys with low nickel contents and onlysmall additions of further alloying elements have in turn poorerproperties, for example with regard to mechanical strength and ductilityor with regard to their corrosion resistance in aggressive media.

SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a metal alloy,which overcomes the above-mentioned disadvantages of theheretofore-known devices and methods of this general type and whichprovides for an alloy which has the same advantageous properties as theprior art alloys, in particular as the alloy NiCu30Fe, but which howevercontains a much reduced proportion of nickel in comparison with thelatter, as a result of which it is significantly less expensive than theknown alloy.

With the foregoing and other objects in view there is provided, inaccordance with the invention, a copper-nickel metal alloy that isprimarily formed of copper, nickel, magnesium and iron. The mainconstituents are copper and nickel. The contents of magnesium and ironare increased considerably in comparison with the prior art conventionalalloys. The novel alloy according to the invention has the followingconstituents in the following proportions (in % by mass and/or wt. %):

copper  40% to 61% nickel  35% to 45% manganese 3.9% to 10% iron 0.1% to5% other materials (e.g., carbon, silicon, aluminum, at most 2% in totalmagnesium, titanium, chromium, rare earths, molybdenum, yttrium) withthe sum of the individual components adding to 100% by mass or 100% byweight.

On account of its much lower proportion of nickel, this alloy issignificantly less expensive than the known nickel-copper alloys,without its properties being made any worse than the known alloys. Onaccount of the much higher proportion of manganese in comparison withthe prior art, this alloy also has particularly high heat resistance,which is required for many applications.

This alloy preferably has the following proportions (in % by mass and/or% by weight):

copper  46% to 59% nickel  37% to 42% manganese 3.8% to 7% iron 0.2% to5% other materials at most 2% in total. with the sum of the selectedcomponents adding to 100% by mass or 100% by weight.

-   -   with the sum of the selected components adding to 100% by mass        or 100% by weight.

A specific preferred alloy has the following constituents in thefollowing proportions (in % by mass or wt. %):

copper 55.03% nickel 39.66% manganese 4.64% iron 0.46% carbon 0.05%silicon 0.06% aluminum 0.02% magnesium 0.03% titanium 0.01% chromium0.02% other materials 0.02%

A further preferred alloy has the following constituents in thefollowing proportions (in % by mass and/or % by weight):

copper 52.87% nickel 39.16% manganese 3.98% iron 3.75% carbon 0.05%silicon 0.09% aluminum 0.03% magnesium 0.03% titanium 0.01% chromium0.02% other materials 0.01%

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is described herein as embodied in metal alloy,it is nevertheless not intended to be limited to the details shown,since various modifications and structural changes may be made thereinwithout departing from the spirit of the invention and within the scopeand range of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of the four alloysrepresenting specific embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION Example 1

In this example the alloy has the following constituents in thefollowing proportions (in % by mass and/or % by weight):

copper  40% to 61% nickel  35% to 45% manganese 3.9% to 10% iron 0.1% to5% other materials, such as carbon, silicon, at most 2% in totalaluminum, magnesium, titanium, chromium, rare earths, molybdenum,yttrium with the sum of the selected components adding to 100% by massor 100% by weight.

Example 2

In this example the alloy has the following constituents in thefollowing proportions (in % by mass and/or % by weight):

copper  46% to 59% nickel  37% to 42% manganese 3.8% to 7% iron 0.2% to5% other materials, such as carbon, silicon, at most 2% in totalaluminum, magnesium, titanium, chromium, rare earths, molybdenum,yttrium with the sum of the selected components adding to 100% by massor 100% by weight.

Example 3

In this example the alloy has the following constituents in thefollowing proportions (in % by mass and/or % by weight):

copper 55.03% nickel 39.66% manganese 4.64% iron 0.46% carbon 0.05%silicon 0.06% aluminum 0.02% magnesium 0.03% titanium 0.01% chromium0.02% other materials 0.02%

Example 4

In this example the alloy has the following constituents in thefollowing proportions (in % by mass and/or % by weight):

copper 52.87% nickel 39.16% manganese 3.98% iron 3.75% carbon 0.05%silicon 0.09% aluminum 0.03% magnesium 0.03% titanium 0.01% chromium0.02% other materials 0.01%

All of these alloys have a comparatively high proportion of copper and acomparatively low proportion of nickel, as a result of which they arecomparatively low in cost in comparison with known Ni—Cu alloys onaccount of the considerable difference in the price of nickel andcopper. Quite apart from this, these alloys are highlycorrosion-resistant, have high strengths and can be processed very wellon account of their very homogeneous structure, as a result of whichthey can be used in a wide variety of areas.

For example in comparison with NiCu30Fe, the alloy according to Example3 and the alloy according to Example 4 have under the same processingconditions in rolling, drawing, intermediate annealing and finalannealing very similar mechanical values on round and flat products,which has very favorable effects on their processability: in Table 1below, the tensile strengths Rm (in N/mm²) and the elongation tofracture A200 (in %, based on a measured length of 200 mm) are comparedbetween the alloy according to Example 3, the alloy according to Example4 and the known alloy NiCu30Fe, in each case in the form of round wireof 1.80 mm in diameter and flat wire of 12.7×0.38 mm, bothsoft-annealed.

TABLE 1 Round wire Flat wire Rm (N/mm²) A200 (%) Rm (N/mm²) A200 (%)Alloy according to 561 34 533 29 Example 3 Alloy according to 576 33 54728 Example 4 Alloy NiCu30Fe 547 34 525 29

The mechanical values of all three alloys compared are to be consideredas the same within the usual batch-dependent variations. Similarly, forexample, the stability with respect to softening during brazing attemperatures of 600° C. and above is to be considered as equally good,much better than in the case of copper-nickel alloys without these highmanganese and iron contents.

A further example of the comparatively good properties of the alloysaccording to Example 3 and according to Example 4 in comparison withalloys with a higher nickel content is the comparatively good corrosionbehavior of the alloys according to Example 3 and according to Example 4as compared with NiCu30Fe. The results of two comparative corrosiontests are given below:

a) Test in 62% CaCl₂ at 120° C. for 5 days:

The loss in weight (g/m² h) in the case of NiCu30Fe is 0.010, in thecase of the alloy according to Example 3 it is 0.014, i.e., the alloyaccording to Example 3 is approximately 71% as corrosion resistant underthese conditions as NiCu30Fe, with a nickel content of about 59% incomparison with NiCu30Fe, and, like NiCu30Fe, also shows no signs ofharmful pitting.

b) Test in 27 g/l of NaCl at 80° C., 6 bar H₂S, 6 bar CO₂ for 14 days:

The loss in weight (g/m² h) in the case of NiCu30Fe is 0.0186, in thecase of the alloy according to Example 4 it is 0.0100, i.e. the alloyaccording to Example 4 is approximately 186% (that is almost twice) ascorrosion resistant under such conditions as NiCu30Fe, with a nickelcontent of about 59% in comparison with NiCu30Fe, and, in the same wayas NiCu30Fe, also shows no signs of harmful pitting.

1. A copper-nickel metal alloy, consisting essentially of the followingconstituents in the following proportions (in % by mass and/or % byweight): copper  40% to 61% nickel  35% to 45% manganese 3.9% to 10%iron 0.1% to 5% other materials at most 2% in total. with the sum of theselected components adding to 100% by mass or 100% by weight.


2. The metal alloy according to claim 1, having the followingproportions (in % by mass and/or % by weight): copper  46% to 59% nickel 37% to 42% manganese 3.8% to 7% iron 0.2% to 5% other materials at most2% in total. with the sum of the selected components adding to 100% bymass or 100% by weight.


3. The metal alloy according to claim 1, consisting of copper, nickel,manganese, iron, and other materials in the following proportions (in %by mass and/or % by weight): copper 55.03% nickel 39.66% manganese 4.64%iron 0.46% other materials 0.21%.


4. The metal alloy according to claim 3, wherein said other materialsare present in the following proportions (in % by mass and/or % byweight of the total alloy): carbon 0.05% silicon 0.06% aluminum 0.02%magnesium 0.03% titanium 0.01% chromium 0.02% further materials 0.02%


5. The metal alloy according to claim 4, wherein said further materialsare selected from the group consisting of the rare earths, molybdenum,and yttrium.
 6. The metal alloy according to claim 1, consisting ofcopper, nickel, manganese, iron, and other materials in the followingproportions (in % by mass and/or % by weight): copper 52.87% nickel39.16% manganese 3.98% iron 3.75% other materials 0.24%.


7. The metal alloy according to claim 6, wherein said other materialsare present in the following proportions (in % by mass and/or % byweight of the total alloy): carbon 0.05% silicon 0.09% aluminum 0.03%magnesium 0.03% titanium 0.01% chromium 0.02% further materials 0.02%.


8. The metal alloy according to claim 7, wherein said further materialsare selected from the group consisting of the rare earths, molybdenum,and yttrium.